Why Study Orioles?

Baltimore Oriole © Richard Johnson, Mass Audubon
Baltimore Oriole © Richard Johnson, Mass Audubon

This is the question we hoped to answer when we started asking people in eastern Massachusetts to help us look for Baltimore Orioles in the spring of 2005. It is a deceptively simple question that raises many other questions about what is happening to our native birdlife. Here are some of them:

What makes us think Baltimore orioles might be declining?

In 1966 Chandler Robbins and others at the Patuxent Wildlife Research Center in Maryland founded the Breeding Bird Survey (BBS) to monitor the status and trends of bird populations on a continent wide basis. The original concern was bird population declines resulting from indiscriminate use of pesticides, but as threats to birdlife have proliferated in recent decades the BBS has become our best source of reliable data on the status of North American birdlife overall.

The survey consists of 24.5 mile roadside routes along which volunteers stop every half mile and record all the birds they can see or hear in a three minute interval. There are now more than 4100 survey routes run annually, and the Breeding Bird Survey is coordinated jointly by the U.S. Geological Survey and the Canadian Wildlife Service.

If we look at the record for Baltimore oriole, the BBS tells us that there has been a statistically significant annual decline of 0.7% continent wide from 1966 to 2004. In the Northeast region (USFWS Region 5) the rate of decline was 0.9% per year; Massachusetts surveys detected a 2.3% annual decline. Furthermore if we look at the most recent decades (1980-2004), the decline in Massachusetts increases to 3.0% per year.

That doesn't sound too bad. Aren't orioles a long way from being endangered?

That's what residents of the U.K. thought when they started detecting small declines in common birds of the countryside such as lapwings, song thrushes and skylarks. But the declines continued and within a couple of decades, populations of the once abundant and ubiquitous skylark had dropped by more than 50% with many other species similarly devastated.

 

But there still seem to be lots of orioles around. Does it make any sense to spend time surveying relatively common birds?

Actually, it does. We now know from bitter experience that once birds become endangered, it is much more difficult - and astronomically more expensive - to try to restore their populations than if we identify problems early on and stem the causes of the decline.

Do we know why orioles seem to be losing ground?

No! And that's another reason to have lots of volunteers out paying attention to the orioles in their communities. Certainly there are many possibilities: habitat destruction, an increase in predators and nest parasites, pesticides, increased mortality during migration or on the wintering grounds. One of the things we have already learned from the Oriole Project is that, while orioles are still easy to find in many places (once you know the song!), they are strikingly absent from other places that seem like ideal habitat. If we can figure out why, we may be able to help maintain local populations.

What can reporting orioles in my neighborhood tell us about how orioles are doing?

If enough people keep track of "their" orioles, from specific locations -e.g. the ones that nest in their backyard or their favorite community walking trail - and report them to us year after year, we will have a good basis for monitoring population changes. Animal populations fluctuate naturally over time in response to a variety of conditions, e.g. food availability. Perhaps we will find that what seems like a significant decline in orioles now will reverse itself in the next decade. It will be just as valuable—and much more heartening—to find that orioles aren't in trouble as to determine that they are. Paying attention to a particular bird species is also a great way to take the pulse of the environment we all share.

Are there other species like Baltimore oriole that are not on any endangered species list, but seem to be getting less common?

Yes, quite a few, for example: American kestrel, whip-poor-will, brown thrasher, field sparrow, eastern towhee, and eastern meadowlark. As in the British scenario, these were once among the most common and widespread birds of the Commonwealth. All now show a downward trend and some appear to be in steep decline.

Is anyone tracking them?

The Oriole Project has been a pilot effort to see if we could collect significant data from a large number of "citizen scientists." (The answer is a resounding "Yes.") It is part of a larger concept we call Birds to Watch that will monitor populations of vulnerable but not yet endangered birds species with the help of volunteers.